Manhole covers are well known access points for various utilities equipment. The covers allow cars and other vehicles to traverse the road without falling into the hole itself. Yet, the covers, approximately fifty pounds each, can be removed for required maintenance. Manhole covers, found along many paved roadways, tend to be spaced between one hundred and five hundred feet apart.
The covers are generally entrenched with rock, tar, sand and dirt. A worker must hook the cover with a pry bar or other equipment and lift. While one cover is a substantial task, removing multiple covers is daunting. Various tools have been developed to ease this task.
For instance, Schmitz et al. (U.S. Pat. No. 5,035,336) and Quarr et al. (U.S. Pat. No. 4,789,072) disclose a Compact Compressible Manhole Cover Lifter and a Hydraulic Manhole Cover Lifter respectively. The lifter is generally an inverted U-shaped piece of equipment that can engage a cover mechanically or magnetically, using either a hydraulic system or winch to lift the cover.
Taylor (U.S. Pat. No. 6,164,898) teaches a Manhole cover Removal Apparatus and Method. A reciprocating member mounted on a vehicle lowers to grasps a cover ad raises to lift the cover.
Agesen (U.S. Pat. No. 3,152,708) discloses a Tool for Lifting Manhole Covers. A lever with wheels, mounted as a fulcrum, applies pressure to a chain joined to the cover.
Mochizuki et al. (U.S. Pat. No. 4,662,607) discloses yet another device for removing manhole covers, entitled Apparatus for Operating Manhole Cover. This device, similar to Agesen, essentially has a lever with wheels, mounted as a fulcrum, which applies pressure to a hanging hook mechanism joined to the cover.
Golding (U.S. Pat. No. 4,826,388) teaches a Manhole Cover Lifter. A key is located in the manhole keyhole and a lever provides the mechanical advantage for lifting the manhole cover.
Chick (U.S. Pat. No. 5,292,107) teaches a Sewer Cover Lifting Tool. This essentially wheeled hand lever tool lifts covers from the side.
Each of the devices are complex, cumbersome and unstable. One device, Lassiter, which is a little less cumbersome than the aforementioned devices is not taught to be used with manhole covers. Lassiter (U.S. Pat. No. 2,804,979) teaches a Portable Lifting Apparatus. A wheeled truck with spaced side frame members carry a boom that may be moved along an arcuate path.
What is needed is a manhole cover remover that is compact for transport and stable in operation. The remover should provide god mechanical advantage and ease of moving, preferably with handles positioned in an easy to reach location. Desirably, it should attach and detach from a vehicle and be usable whether or not it is attached to a vehicle.